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ICT has a large potential to be useful in health care. While hospitals are now often equipped with advanced tools using digitized analysis and embedded technology for operations etc., IT based administrative tools used to coordinate activities and communicate knowledge in the area of health care have not yet been generalized. The effect of these IT/ICT tools on the life of people world over has been...
The radiation properties of a circular patch antenna with u-slot designed on glass epoxy FR-4 substrate are obtained and compared with that of a normal circular patch antenna designed under identical conditions. The modified antenna not only resonates at two different frequencies allotted by IEEE 802.16 working group for lower band (2.495-2.695 GHz) operation for WiMax systems but also presents marked...
We study a sensor node with an energy harvesting source. In any slot, the sensor node is in one of two modes: Wake or Sleep. The generated energy is stored in a buffer. The sensor node senses a random field and generates a packet when it is awake. These packets are stored in a queue and transmitted in the wake mode using the energy available in the energy buffer. We obtain energy management policies...
This paper presents the experimental results of a repetitive Marx generator being developed at BARC. Effect of lead inductance, sparkgaps' alignment, charging inductor, ground inductor and shielding has been studied. Two types of configurations have been adopted in order to reduce the erected Marx inductance and results are compared. In this Marx generator plus-minus charging scheme was adopted for...
We address the problem of estimating a random field via a wireless sensor network. We use a Multiple Access Channel (MAC) as the basic building block for such a network. For Gaussian sources over Gaussian MACs, we show that Amplify and Forward scheme (AF) performs well in such sensor network scenarios where the battery power is at a premium. We then extend this result to the hierarchical network scenario...
Tuning of the PID controller in a varying environment is extremely difficult. For this purpose one has to use the adaptive PID controller. In the present paper a novel method for fast tuning of the PID controller has been presented and implemented on designed and developed hardware around the 89C51 microcontroller. Varying environment in the very old existing MLW-MK70, former East German bath has...
A fully computer controlled system has been designed and developed for measuring the density of solids by hydrostatic weighing method. The hardware of the system has been developed around 89C51 microcontroller. In this setup density of the unknown sample is determined with the help of mean density of the two solid density standards. The overall uncertainty has been obtained to be of the order of 0...
We resolve complex electron autoionization dynamics in molecules in real time for the first time, where a second electron cannot be ejected from O2 until the internuclear separation of the fragments is >30 Aring.
Wireless networks suffer from high packet loss-rates and variations in delay and bandwidth. This makes it difficult for conventional transport protocols like TCP to operate efficiently over such networks. We presented multi-path loss tolerant transport protocol (MPLOT) in to counter such lossy and volatile conditions. MPLOT uses multiple paths for data transfer such that at an aggregate level, the...
Cognitive radio networks have the ability to efficiently utilize the radio spectrum by allowing unlicensed users to communicate in the licensed frequency bands. Transmit beamformers can be designed by setting constraints on the interference temperature of the licensed users and signal to interference and noise ratios (SINRs) of the cognitive users. This design is however very sensitive to errors in...
We consider the problem of transmission of correlated discrete alphabet sources over a Gaussian multiple access channel (GMAC). A distributed bit-to-Gaussian mapping is proposed which yields jointly Gaussian codewords. This can guarantee lossless transmission or lossy transmission with given distortions, if possible. The technique can be extended to the system with side information at the encoders...
A robust signal forwarding technique for wireless sensor and mesh networks using semidefinite constraints is proposed. The scheme considers a multiple source destination scenario where a set of relays assists forwarding signals from sources to destinations. In our work we consider a realistic environment where actual channel state information (CSI) available to the relays are in error. We propose...
We consider the transmission of correlated Gaussian sources over orthogonal Gaussian channels. It is shown that the amplify and forward (AF) scheme which simplifies the design of encoders and the decoder, performs close to the optimal scheme even at high SNR. Also, it outperforms a recently proposed scalar quantizer scheme both in performance and complexity. We also study AF when there is side information...
Cooperative communication using rateless codes, in which the source transmits an infinite number of parity bits to the destination until the receipt of an acknowledgment, has recently attracted considerable interest. It provides a natural and efficient mechanism for accumulating mutual information from multiple transmitting relays. We develop an analysis of queued cooperative relay systems that combines...
Airborne links are playing an increasingly important role in defense and military scenarios. This makes it important to investigate the performance of existing transport protocols over such links. Airborne links experience high variation in quality due to mobility, weather and other effects such as blockage. This translates to high loss rate environments for which current protocols are not designed...
We propose a novel, energy-aware, routing protocol for quality-of-service (QoS) support in an infrastructure-less ad-hoc network. Our stability-based, QoS-capable ad-hoc on-demand distance vector (SQ-AODV) protocol is an enhancement of the well-known ad-hoc on-demand distance vector (AODV) protocol. Our protocol utilizes a cross-layer approach, in which information about residual node energy is used...
In the present paper, a pentagonal microstrip patch antenna is proposed to achieve compact size, broadband and dual frequency operation. It is observed that the proposed antenna is radiating at two different frequencies without much loss in its radiation performance showing broad band performance. Both these resonance frequencies lie in the median band (3.25 to 3.85 GHz) of WiMax systems, a new standard...
A circular patch antenna with a narrow slit is proposed to achieve multi frequency, dual band operation. The proposed antenna radiates at four different frequencies with sufficiently high matching with probe feed system. Among these four frequencies two frequencies 2.62 GHz and 5.82 GHz lies in lower and upper frequency band respectively of Wi-Max application created by IEEE 802.16 working group....
This communication presents a comparison in the performance of a normal elliptical microstrip patch antenna with same antenna having loading of sector slits. Required number and dimensions of the slits for bandwidth enhancement are optimized for reliable radiating characteristics. It is found that resonant frequency of the unslotted elliptically patch antenna is about 5.62 GHz, with an operating bandwidth...
A modified rectangular patch antenna with an air gap in between the two substrate layers of patch antenna is analyzed using the IE3D simulation software to achieve compact size, lightweight and wide band operation. With variation in patch geometry and insertion of thin air gap, the bandwidth of traditional microstrip antenna which varies between 1 - 2 % is improved to more than 33.5%. Different radiation...
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